Yet more on the fossil record's on going hostility toward the Darwinian narrative.

Fossil Friday: Fossil Elephant Shrews and the Abrupt Origin of Macroscelidea 

Günter Bechly 

This Fossil Friday we look into the origins of the placental mammal order Macroscelidea, which comprises the very strange but uber-cute elephant shrews or sengis. These small insectivorous mammals are speedy runners endemic to Africa, where they occur in 20 living species (Heritage et al. 2020). With their long mobile snouts they look a bit like the fictitious snouter animals described by the German zoologist Gerolf Steiner in his satirical book Bau und Leben der Rhinogradentia (Stümpke 1967), which has a kind of cult status among German-speaking animal lovers. Elephant shrews are sometimes considered to be living fossils (Novacek 1984) and their origin is believed to go back 57.5 million years in the Paleocene with a subsequent divergence of the crown group in the early Oligocene about 33 million years ago (Heritage et al. 2020: fig. 7) and its main diversification in the Miocene correlated with aridification events in Africa (Douady et al. 2003). 

Such a deep division of the main groups of extant Macroscelidea is also indicated by another recent molecular study (Krásová et al. 2021). So much for the theory, but let’s check what the actual fossil record, mostly consisting of jaw fragments and isolated teeth, really says. As noted by Stevens et al. (2021), “unravelling the origin and affinities of macroscelideans (also termed sengis, or elephant shrews) has long presented a palaeontological puzzle.” According to the technical literature the fossil record of the order Macroscelidea and its assumed fossil relatives spans from the Early Eocene to the Pleistocene (Patterson 1965, Butler 1995, Holroyd 2009, Asher & Seifert 2010, Naish 2013), and was always restricted to the African continent (for a possible exception see below). The earliest fossils of Macroscelidea are said to be 45.6 million years old (Hartenberger 1986, Holroyd 2010, Seiffert 2010a). 

Considerable Scientific Debate 

Of course, the question of the earliest fossil record of Macroscelidea hinges crucially on the question of which fossil taxa qualify as Macroscelidea in the first place. Unfortunately, this latter point is a matter of considerable scientific debate with very different suggestions for the composition, subdivision, and classification of Macroscelidea. We here follow the most recent work by Senut & Pickford (2021), but include in our discussion some more questionable fossil taxa considered by Holroyd (2010) and Hooker & Russell (2012) (see the Appendix for a classification of all genera with age ranges of their fossil record). 

The oldest unequivocal Macroscelidea are the fossil taxa Eorhynchocyon rupestris (Rhynchocyonidae), Namasengi mockeae (Macroscelididae: Namasenginae), Promyohyrax namibiensis (Myohyracidae), Afrohypselodontus minus and A. grandis (Afrohypselodontidae), all described by Senut & Pickford (2021) from the tufas of the Eocliff locality in Namibia. They demonstrate the simultaneous abrupt appearance of all four families of elephant shrews in the Middle Eocene (Bartonian/Priabonian, 40.4-37.2 mya), which is not exactly what Darwinism would predict. A somewhat older Middle Eocene record could be a single tooth (specimen SN 10’08 ) of an unnamed species from the Sperrgebiet in Namibia described by Pickford et al. (2008: 470), which is of probable Lutetian age (47.8-41.2 mya) and may belong to an early ancestor of Myohyracidae. 

Previously, the oldest crown group macroscelideans were the rhychocyonids Oligorhynchocyon songwensis from the Late Oligocene (25.2 mya) Nsungwe Formation in Tanzania (Stevens et al. 2021) and Miorhynchocyon meswae from the Early Miocene (22-21 mya) of Kenya (Butler 1984, Holroyd 2010, Heritage et al. 2020). 

The Pliocene 

genus Mylomygale was a rodent-like herbivore (Naish 2013) and is classified in a separate subfamily Mylomygalinae (Camp et al. 1953, Patterson 1965, Holroyd 2010). However, “Corbet & Hanks (1968) pointed out that it shows a considerable resemblance to Macroscelides, and it may be a specialized member of the Macroscelidinae” (Butler 1995). Until recently, Mylomygale was only known from Early Pleistocene cave sediments in South Africa, contemporaneous with the close-by locality of the famous Taung Child. Now, this genus has also been found in Middle Pliocene paleokarst of South Africa (Senut et al. 2022). 

Another group that is very close to modern macroscelideans but rather resembled hyraxes is the extinct family Myohyracidae (Patterson 1965, Van Valen 1967, Butler 1984, 1995, McKenna & Bell 1997, Naish 2013), which initially indeed was misidentified as fossil hyraxes. It is mainly known from the Miocene, but the earliest representatives are Myohyrax and Promyohyrax from the Late Eocene of Namibia (Senut & Pickford 2021). The above mentioned unnamed specimen from the Lutetian of Namibia might be a basal Myohyracidae, since Pickford et al. (2008) found that it has “a morphology that could represent the ancestral morphotype for Myohyrax and Protypotheroides.”

Finally, there is the new macroscelidean family Afrohypselodontidae erected by Senut & Pickford (2021) from the Late Eocene of Namibia, which is unique with its ever-growing rootless cheek teeth. 

Two other extinct taxa that were excluded from unequivocal Macroscelidea by Senut & Pickford (2021) but are quite likely indeed stem macroscelideans are the Metoldobotidae and Herodotiidae. The later could extend the fossil record to 55.8 million years ago, which would perfectly align with the brief Paleogene window of time, when most of the placental orders abruptly appear in the fossil record.

The genus Metoldobotes from the early Oligocene of Fayum in Egypt was often considered the oldest and largest unequivocal Macroscelidae (Patterson 1965, Simons et al. 1991, Asher & Seiffert 2010, Stevens et al. 2021). Strangely, it would also be “one of the most derived macroscelideans” (Simons et al. 1991). Tabuce et al. (2001) suggested that Metoldobotes is the sister group to Myrohyracidae and living elephant shrews, while Seiffert (2007) found strong bootstrap support for a sister group relationship with crown group Macroscelidea. However, in the most recent study this position has been questioned by Senut & Pickford (2021), who considered Metoldobotidae to be only doubtfully related to Macroscelidea, mainly because of its poorly preserved and scanty fossil record. As an interesting side note, Naish (2013) speculated that Metoldobotes may have been the only venomous sengi because of a conspicuous groove in the lower third incisor, but also cautioned that many mammals have such grooves without being venomous. 

The extinct family Herodotiidae is more primitive and older, with some similarities to the Paleogene “condylarthrans” (Butler 1995; see below), but still has often been included as subfamily Herodotiinae in a more widely understood family Macroscelidae (Simons et al. 1991, Butler 1995, Tabuce et al. 2001, 2012, Benoit et al. 2013, Tabuce 2018). The studies by Seiffert (2007) and Asher & Seiffert (2010) “reviewed arguments for and against including herodotiines (Nementchatherium, Chambius and Herodotius) in the Macroscelidea.” According to Seiffert (2007) “the Eocene herodotiines Chambius and Herodotius are generally considered to be primitive macroscelideans” (e.g., Hartenberger 1986, Tabuce et al. 2007, Seiffert 2010b), with a fossil record that extends to the Early or early Middle Eocene Chambi Massif in Tunisia, where Chambius was first discovered.  

However, in Seiffert’s own analysis (Seiffert 2003, 2007) the genera Herodotius and Chambius never clustered with Macroscelidea but with aardvarks in some of the trees, and in others with pseudoungulates, paenungulates, or hyraxes. Senut (2008) concluded that “the Palaeogene Macroscelididae from Northern Africa classified in the Herodotiinae (Simons et al., 1991), might not be ancestral to any of the Miocene to Recent Macroscelididae.” However, this result could be based on undersampling of data as a larger updated data set (Seiffert 2010b: fig. 14) again placed herodotiines with Macroscelidea. Benoit et al. (2013) studied the evolution of the middle and inner ear of elephant shrews and in their cladistic study resolved Chambius as basal-most representative, but they ignored the study of Seiffert (2007). I think the case for a macroscelidean relationship is reasonably well supported, which would extend the fossil record of Macroscelidea to about 55.8 million years ago. 

Uncertain and Doubtful 

All remaining candidates as earlier stem macroscelideans are much more uncertain and doubtful. They mostly belong to a group of enigmatic fossil mammals from the Paleocene and Eocene that was previously classified within the highly polyphyletic ungulate-like order “Condylarthra” in the family Hyopsodontidae, which seems to be a likewise polyphyletic waste basket taxon (Tabuce et al. 2001, 2006, Zack et al. 2005a, Halliday et al. 2015). The study by Halliday et al. (2015: fig. 1) mentioned a close affinity of Hyopsodontidae and Macroscelides as “current consensus,” but found that the “case of the macroscelidean relationships … depends on the assumption that apheliscid ‘condylarths’ fall within Hyopsodontidae,” which they failed to establish in their own analysis. 

Zack et al. (2005b) removed the apheliscine and louisinine genera from Hyopsodontidae and placed them in a separate family, Apheliscidae. This family Apheliscidae comprises several genera and species including Haplaletes andakupensis and Litomylus orthronepius, which could be the oldest stem macroscelideans by far with an estimated stratigraphic range of 66.043-63.3 mya. A relationship of Apheliscidae with Macroscelidea was supported by several studies (Simons et al. 1991, Zack et al. 2005a, Penkrot et al. 2008), which also postulated a possible Holarctic origin of this subgroup of Afrotherian mammals. This would be strange indeed, but also on anatomical grounds such a relationship with Macroscelidea still has to be considered as highly controversial, since Halliday et al. (2015) instead recovered Apheliscidae as a basal member of the Laurasiatheria, thus not even as afrotherian mammals. 

A Big Question Mark 

As just mentioned, Zack et al. (2005b) had transferred Louisininae from Hyoposodontidae to the reinstated family Apheliscidae. Louisinines also include the species Cingulodon magioncaldai and Monshyus praevius from the Hainin Formation in Belgium, which yielded the oldest Cenozoic mammalian fauna of Europe with its estimated age range of 66.043-61.7 mya (Sudre & Russell 1982, De Bast & Smith 2017). Several authors considered a possible relationship of louisinines with Macroscelidea (e.g., Hartenberger 1986, Simons et al. 1991, Tabuce et al. 2001, 2007, Holroyd & Mussell 2005, Zack et al. 2005a; see Benoit et al. 2013). This was indeed strongly suggested by Hooker & Russell (2012), who elevated them to a separate family, Louisinidae, in the stem group of Macroscelidea.  

Tabuce (2018) tentatively and with a big question mark concurred with this result, even though the study had significant flaws that were highlighted by De Bast & Smith (2017) who commented:

Hooker & Russell (2012) followed this hypothesis in the last revision of the family; however, they relied on a cladogram that lacked any extant member of Macroscelidea and in which most basal dichotomies are found only in the majority-rule consensus but not in the strict consensus tree. Here we place the family in Eutheria without further precision because we believe that the characters shared by Louisinidae and Hyopsodontidae with Macroscelidea are convergences due to the development of saltatorial capacities. 

Two other hyopsodontid “condylarths,” i.e. Teilhardimys (= Microhyus) and Paschatherium,were recovered as very basal stem group representatives of Macroscelidea by Zach et al. (2005a) and Tabuce et al. (2006). Zach et al. (2005b) classified these two genera in Louisininae within Apheliscidae. In the cladogram of Tabuce et al. (2007) the North American apheliscines are closer to Macroscelidea, but the European louisinines “Microhyus” and Paschatherium closer to Paenungulata. On the other hand, Cooper et al. (2014) found that “the consistent recovery of the European louisinids Paschatherium and Teilhardimys as stem perissodactyls challenges the view that they are afrotherian macroscelideans.” The seminal work by Halliday et al. (2015) on Paleocene mammal affinities found neither Teilhardimys nor Apheliscidae to be closely related with Macroscelidea and indeed did not even support any of the mammalian supergroups (Xenarthra, Afrotheria, Euarchontoglires, and Laurasiatheria) as monophyletic unless constrained with molecular data. It must be really emphasized again: the very same fossils were in some studies resolved as close relatives of the order Macroscelidea and Paenungulata within the supergroup of Afrotheria, and in other studies recovered as close relatives of the unrelated order Perissodactyla (odd-toed ungulates) in the different supergroup Laurasiatheria.  

Have you ever heard any physicists hotly debating if a certain particle is a fermion or a boson? All such substantial problems were likely the reason that Senut & Pickford (2021) in the most recent work on macroscelidean evolution considered Louisinidae to be doubtfully related to Macroscelidea.

In their mentioned revision of Louisinidae, Hooker & Russell (2012) suggested in their maximum parsimony cladogram (see above for flaws in this analysis) that the genus Adunator and the families Adapisoricidae and Amphilemuridae successively represent the most basal branches of the macroscelidean lineage. Apparently, this was not accepted by any other authors (compare Tabuce et al. 2018), but still made it into the Paleobiology Database and the German Wikipedia. 

In spite of some similarities with hyopsodontid condylarths, these taxa are generally considered to be related to erinaceomorph insectivorans (hedgehogs) of the order Eulipotyphla (Russel 1964, Van Valen 1967, Novacek et al. 1985, Halliday et al. 2015). Senut & Pickford (2021) did not even bother to list them among their “families of doubtful or uncertain macroscelidean affinities.”

Last but not least, we must briefly discuss the leptictidians, an enigmatic group of bipedal mammals from the Paleogene. Asher & Seiffert (2010) placed the genus Leptictis from the Late Eocene and Oligocene of North America as sister group to Macroscelidea in their tree of Afrotherian phylogeny and biostratigraphic distribution. This phylogenetic position of leptictids was also supported in the cladograms of Zack et al. (2005a: fig. 3c), Hooker & Russell (2012), and O’Leary et al. (2013). The genus Leptictis and its relatives are generally recognized as a distinct order Leptictida, which even includes the Late Cretaceous genus Gypsnonictops. 

This would of course be an extremely interesting and very unusual dating for a subgroup of Afrotheria and alleged close relative of living elephant shrews. However, according to other experts (e.g. Wible et al. 2009), including the most recent study (Halliday et al. 2015), the Leptictida instead belong into the paraphyletic stem group of placental mammals, and therefore do not even represent real eutherians. Similarities of leptictids and macroscelideans therefore have to be considered as convergences, as already suggested by Butler (1995). Likewise, Meehan & Martin (2010) noted that “the morphology of leptictidans was highly convergent to that of extant macroscelideans, due to similar ecological specialisations to insectivory, digging, and saltatory locomotion” (Halliday et al. 2015). 

An Apparently Simple Question 

As you likely have realized by now, it can get pretty complicated to answer the apparently simple question of what the earliest fossil record of a certain group is, or even to find a consensus about what the group is. Anyway, from the above we can at least conclude that the oldest fossil record of unequivocal Macroscelidea is about 55.8-40 mya and that of the more doubtful alleged stem group about 66-56 mya. While there are some aberrant rodent-like and hyrax-like fossil elephant shrews, we do not find any fossil evidence for a gradual building of the distinct macroscelidean body plan during the Paleogene and Neogene periods (formerly called Tertiary). Likewise their theoretically predicted stem group in the Upper Cretaceous is totally missing in the fossil record, since Leptictida turned out to be stem eutherians. Just as all the other placental mammal orders, elephant shrews appeared abruptly on the scene, unless “hyopsodontids” like Louisinidae should indeed turn out to be stem group macroscelideans, which is still far from certain (see above). But even then, there would remain a large morphological gap between the condylarth-like stem taxa and unequivocal macroscelideans. 

Just like its internal classification, the systematic affinities of the order Macroscelidea used to be a big mess, with very different candidates discussed as putative closest relatives, such as Archonta (treeshrews, colugos, and primates), Glires (rabbits, hares, and rodents), Eulipotyphla (insectivores), Tubulidentata (aardvarks), and Afrosoricida, as well as extinct Condylarthra (Patterson 1965, Simons et al. 1991, Butler 1995, Tabuce et al. 2001, Asher & Seiffert 2010, Naish 2013, Stevens et al. 2021). Rathbun (2005) therefore noted that “few mammals have had a more colourful history of misunderstood ancestry than the elephant-shrews.” Only after the advent of phylogenomics have they been recognized as members of the Afrotheria clade (Nishihara et al. 2005, Seiffert 2003, 2007, Asher & Seiffert 2010). Next Fossil Friday we will look into another member of the Afrotheria, i.e., the order Afrosoricida that includes golden moles, otter shrews, and the iconic tenrecs of Madagascar. Stay tuned for more evidence on abrupt appearances in the mammalian fossil record. 

The ancient wisdom of the ents.

 At nautilus: the ancient wisdom stored in trees 

Uncommon descent 

What’s the oldest known living thing, and how do we know? Why should we even want to know? The explanation is a history of curiosity and care. It’s about our long-term relationships—spiritual and scientific—with long-lived plants, as long as long can be. It’s all about trees.

A tree is a plant that people call a tree—a term of dignity, not botany.

Although people construct the meaning of “trees” and assign age value to the vascular plants they call “ancient trees,” people cannot themselves create life that grows in place for centuries. Exclusively, solar-powered organisms enact that miracle. Among plants, there are ephemerals, annuals, biennials, perennials—and, beyond them all, perdurables, thousand-year woody life-forms. 

INTO ETERNITY: Individual bristlecone pines, such as this one photographed in Utah, can live for close to 5,000 years. By sectioning off dying parts of themselves, they’re able to outlast the rise and fall of human empires. Photo by Anthony Heflin / Shutterstock.

As a rule, gymnosperms (flowerless plants with naked seeds) grow slower and live longer than angiosperms (flowering plants with fruits). Gymnosperms include ginkgo (a genus of one), cycads, and every kind of conifer—including yews, pines, firs, spruces, cedars, redwoods, cypresses, podocarps, and araucarias. All these lineages began hundreds of millions of years before the divergence of angiosperms. In effect, the newer, faster competition forced slow growers to retreat to exposed sites and poor soils, adverse niches conducive to oldness. Five thousand years is the approximate limit for nonclonal living under adversity. In plants, the potential for extreme longevity seems to be an evolutionary holdover from the deep past. Only about 25 plant species can, without human assistance, produce organisms that live beyond one millennium, and they are mainly conifers of primeval lineage. The cypress family contains the most perdurables, followed by the pine family. Many relict conifers hang on in limited, vulnerable habitats. The ice ages didn’t help their cause. In general, neither did humans, with their technologies of fire, domestication, and metalworking. Of some 600 conifer species, roughly one-third are endangered, with many genera reduced to a single species. 

A gymnosperm doesn’t so much live long as die longer—or, live longer through dying. The interior dead wood—the heartwood—performs vital functions, mechanically and structurally. In comparison, the thin living outer layer is open to the elements. If damaged by an extrinsic event such as fire or lightning, this periderm doesn’t heal or scar like animal skin. Instead, new cambium covers the injury, absorbing it as one more historical record alongside its growth rings. Thus, an ancient conifer is neither timeless nor deathless, but timeful and deathful. A few special conifers such as bristlecone pine can live through sequential, sectorial deaths—compartmentalizing their external afflictions, shutting down, section by section, producing fertile cones for an extra millennium with the sustenance of a solitary strip of bark. The final cambium has vitality like the first. Longevity doesn’t suppress fecundity. Unlike animals, plants don’t accumulate proteins that lead to degenerative diseases. 

The strongest correlation with long life (elongated death) is chemical. Longevous conifers produce copious resins—volatile, aromatic hydrocarbons like terpenes—that inhibit fungal rot and insect predation. Chemically, bristlecone is off the charts. Its high-elevation habitat offers additional protection from enemies, competitors, and fire, given that they tolerate dryness and cold. In habitats with chronic stress, conifers grow slower and stockier. Slow woody growth generates more lignin, another organic polymer with defensive properties. Stress-tolerant plants prioritize stability over size. Their stuntedness is equal parts adaptation and tribulation. 

Regrowth is another pathway to oldness, an adaptation that appears in both gymnosperms and angiosperms. Certain single-boughed woody species—notably ginkgo, redwood, yew, olive—can recover from catastrophic damage, even the death of the bole. These trees never lose their ability to resprout and regenerate. At the organismal level, they do not senesce, meaning they don’t lose vitality with age. In theory, such a plant is internally capable of immortality, though some external force inevitably ends its life. With particular species and cultivars, humans can force rejuvenation through grafting, pollarding, or coppicing. Plants that normally die young may live long under horticultural care. 

The price of longevity is immobility. At the organismal level, a plant cannot migrate like an animal. Its localism is total. Trees take what comes until something indomitable comes along. Extrinsic mortality may result from a distinct catastrophe, such as fire or gale, or multiple, cumulative stressors. There are limits beyond which even the most deeply rooted organisms can no longer function. Thresholds of water, salinity, and temperature are absolute thresholds. 

Does a naturally occurring tree of great age have value in itself? Foresters and forest ecologists have long debated this question. A century ago, technicians used words like “overage,” “overmature,” and “decadent” to describe standing timber past its prime. Commercial managers saw tree life as individual and rotational, and considered postmerchantable growth to be a biological waste of time. Their business—international markets for wood products—encouraged uniformity in age and size. By contrast, forest ecologists studied the communities in, on, and under each tree—each a world in itself—and saw forest life as processual. The cycle of life required dead and dying trees. Today, foresters meet ecologists halfway: Old trees provide nutrient cycling, carbon storage, and other “ecosystem services.” 

Perdurables are so much more than service providers. They are gift givers. They invite us to be fully human—truly sapient—by engaging our deepest faculties: to venerate, to analyze, to meditate. They expand our moral and temporal imaginations. 

In mythical form, trees appear in creation stories, present at time’s beginning. In graphical form, they represent seasons, cycles, genealogies, algorithms, and systems of knowledge. An olden bough is a bridge between temporalities we feel and those we can only think. This is why Darwin imagined millions of years of evolutionary history as a wide-spreading Tree of Life. Most profoundly, select living conifers—ancient organisms of ancient ancestry—are incarnations of geohistory. Volcanic eruptions, magnetic field reversals, and solar proton events leave signatures in their wood. Through tree-ring science, we see how woody plants register cyclical time and linear time, Chronos (durations) and Kairos (moments), climate and weather, the cosmogenic and the planetary. As multitemporal beings—short, long, and deep time together, in living form—perdurables allow us to think about the Anthropocene without anthropocentrism. They grant emotional access to timefulness.  

The “adaptations” that contribute to trees’ longevity have the hallmarks of design, to enable the organism to weather various threats to its existence. The persistence of these living things is remarkable. The author’s description of some trees reminds me of Tolkien’s description of elves: immortal, but still subject to death by violence. Stewarding Earth’s resources by appreciating the value of these longest-lived keepers of history is commended to us by wisdom. 

Bowing down to the beast?

 Robert Schenk on the religious right's Faustian bargain.

Faith on view 

Brad Reed of Salon writes that Evangelical preacher Robert Schenck criticized Christian conservative support of Republicans in testimony to the House Judicial Committee. He argued that the alliance between the religious right and Republicans came at “a great spiritual cost.”

Reverend Schenck was a prominent activist in the pro-life movement before 2019 and cited the Supreme Court’s recent decision to overturn Roe v. Wade as part of an unequal exchange between Christians and politicians. Schenck later repudiated his anti-abortion position and has preached in more than 40 countries since 1982, including every state in the US.

Reed continues:

The Rev. Robert Schenck, who was once a prominent anti-abortion activist, testified before the House Judiciary Committee on Thursday that he and his fellow conservative Christians made a Faustian bargain with the Republican Party as part of their quest to overturn Roe v. Wade.

During his testimony, Schenck described a meeting he and his fellow evangelicals had with Republican operatives in which they were told that, in order to get what they wanted with Roe, they would have to accept and promote an entire package of right-wing policies that they otherwise might have found objectionable.

In that meeting that I participated in, the conversation went something like this: ‘You guys want Roe v. Wade overturned, we can do that for you, but you take the whole enchilada, you take the whole thing,”‘ he said. “You take everything else that comes with it. Because if you want Roe gone, you have to work with us.”

“From that point on that community that I had served, and still do, made a deal with them devil,” he said. “That deal was, we would support everything on the conservative agenda, whether or not we had conscientious conflict with them. The means were justified by the ends of that.” 

 Ps. Of course the religious left has long had its own Faustian bargain going with the political left and is (if anything) even less self aware re:the spiritual injury they have been doing themselves thereby.